High sulfate expansive soils present special challenges during stabilization. Traditional stabilizers such as lime and cement which are rich in calcium are ineffective in controlling shrink/swell behavior of these soils due to formation of the expansive mineral, ettringite. In this study, two geopolymers synthesized from aluminosilicate sources, fly ash and metakaolin, were investigated to determine their effectiveness in stabilizing shrink-swell behavior of high sulfate expansive soil. Geopolymers were modified with lime and gypsum to improve their efficacy as stabilization agents for sulfate bearing soil. Modifier contents were optimized to achieve maximum reduction in swell potential and at the same time prevent ettringite formation. Microstructural analyses were performed on lime and gypsum added geopolymer to determine the mechanism of modification. Swell tests were conducted on high sulfate soil treated with modified geopolymer at different concentrations and optimum concentration of modified geopolymer required to achieve minimum swell was established.

高硫酸盐膨胀土在稳定过程中面临特殊挑战。由于形成膨胀的矿物钙矾石，传统的稳定剂，例如富含钙的石灰和水泥，在控制这些土壤的收缩/膨胀行为方面无效。在这项研究中，研究了两种由铝硅酸盐来源合成的地聚合物，粉煤灰和偏高岭土，以确定它们在稳定高硫酸盐膨胀土的收缩-膨胀行为方面的有效性。用石灰和石膏改性地聚合物，以提高其作为含硫酸盐土壤稳定剂的功效。优化了改性剂含量，以最大程度地降低溶胀电位，同时防止钙矾石形成。对石灰和石膏添加的地质聚合物进行了微结构分析，以确定改性的机理。在用不同浓度的改性地质聚合物处理过的高硫酸盐土壤上进行了膨胀试验，并确定了达到最小膨胀所需的最佳改性地质聚合物浓度。